Conventionally, so called TN mode liquid crystal displays are largely used in which a liquid crystal having positive dielectric anisotropy is twisted homogeneous aligned between substrates opposed to each other. In the TN mode, however, the liquid crystal molecule in the vicinity of the substrate can cause birefringence due to the driving characteristics so that light leakage can occur, which makes perfect black viewing difficult. While, an in-plane switching-mode liquid crystal display presents a pixel display in a way such that an electric field in parallel with a liquid crystal substrate is formed between pixel electrodes and a common electrode. The liquid crystal display of this type has an advantage, which makes perfect black viewing, which a wide viewing angle is obtained as compared with a TN mode type liquid crystal display in which a vertical electric field to a substrate is formed.
In conventional in-plane switching-mode active matrix liquid crystal display, however, an almost perfect black viewing can be achieved in a direction normal to a panel, whereas in a case where the panel is viewed in a direction deviated from the direction normal to the panel, there has been remained a problem that unavoidable light leakage as a characteristic of a polarizing plate occurs in a direction deviated from the optical axis of the polarizing plates disposed on the top or bottom of a liquid crystal cell with the result is that a viewing angle is narrowed and a contrast is reduced. In another case where the panel is viewed in a direction oblique relative thereto, an optical path of light is longer, which alters an apparent retardation in a liquid crystal layer. Therefore, when viewed at different viewing angles, a wavelength of transmitted light varies, a color of a screen image changes, thereby causing a color shift depending on an observation direction.
Various kinds of proposals have been offered in order to improve reduction in contrast and a color shift depending on a viewing angle in such conventional in-plane switching-mode liquid crystal display(Japanese Patent Application Laid-Open (JP-A) No. 11-133408, JP-A No. 2001-242462). For example, in JP-A No. 11-133408, a proposal has been offered on a technique that compensation layers each with an optical anisotropy are inserted between a liquid crystal layer and respective polarizing plates in pair sandwiching the liquid crystal layer therebetween. This technique is effective for a color shift, but cannot sufficiently suppress a reduction in contrast. In JP-A No. 2001-242462, another proposal has been offered on a technique that first and second retardation plates are inserted between a liquid crystal layer and respective polarizing plates in pair sandwiching the layer therebetween. While it is described in the publication that this technique is effective for improvement on reduction in contrast and color shift, a higher improvement effect has been still desired.